The chemical structure and biological test data that have been systematically collected over the years should be the basis of an automated method for selecting from potential drug accessions those compounds with high probability of antitumor activity, and also selecting the tumor system likely to demonstrate this activity. Such a system will help optimize the utilization of screening resources. The decision-making power of the computer will be used to correlate molecular structure and other physical/chemical properties with known activity in various test systems. Due to the large potential number of such properties and the lack of relevance of most of them, there will be a preliminary project to select combinations of properties which are most informative about activities. At first a system will be developed to aid in pre-selecting drugs for screening. Later, such methods may play a more active role in seeking additional compounds which are promising or not yet adequately represented in our files.